22-06-09 It could be argued that the most difficult job in the oil and gas industry is oilfield services. Most oilfields tend to be located in geographically remote areas, and that's before you even start drilling. The logistics required to extract, process and transfer crude oil or gas would make most companies think twice about even entering the business in the first place.So it was with this in mind that we decided to pay our respects and give you our list of the top 10 world's largest oilfield services companies.

The criteria we have used have been based solely on a company's revenues for 2008. However, there are a couple of anomalies that we should point out.First of all we decided that we would exclude all NOCs and IOCs.Second you will notice Fluor finished sixth on the list, but boasts higher revenues than any other company aside from Schlumberger. The simple explanation is that Fluor operates across a number of industries which accounts for its higher revenues.

Anyone who is au fait with the oilfield services industry will also notice a few glaring emissions. Where is Bechtel, Samsung Heavy Industries, Chiyoda, Hyundai Heavy Industries, SK Engineering, Technip, Tecnicas Reunidas etc.?To be honest a few of the above named companies should maybe have made the top 10, but during our research we found it almost impossible to separate the oilfield services side of their businesses from the rest. All we can do is apologise and promise to compile a list of the top 10 oil and gas contractors in the future.

(Revenues in $) 1. Schlumberger ($ 27.16 bn) Top 1 Largest oilfield services companyWhen Conrad and Marcel founded the initial incarnation of Schlumberger in France back in 1926, I'm sure even they didn't know that it would one day become the largest oilfield services company in the world.Schlumberger now operates in around 80 countries and has a staggering 82,000 employees. The company, registered in the Dutch Antilles and headquartered in Houston, Paris and The Hague supplies numerous products and services including seismic acquisition and processing, formation evaluation, well testing and directional drilling, well cementing and stimulation, artificial lift, well completions and consulting, and software and information management.

The CEO of the company, Andrew Gould, started work in the internal audit department at Schlumberger's Paris office in 1975. Since then he has held a number of positions within the company before assuming his current role in 2003.In the Middle East Schlumberger are involved in numerous large scale projects for companies including Saudi Aramco, including the huge Dharan field, Abu Dhabi National Oil Company (ADNOC), Kuwait Oil Company (KOC) and Qatar Petroleum (QP) among many others.

2. Halliburton ($ 18.28 bn) Top 2 Largest oilfield services companyAlthough Halliburton has to settle for second place, there is no doubt that due to various controversies over the last decade, the company is far more famous than an oilfield operator should. A view, if you read the various disclaimers on its website, shared by Halliburton themselves.

The CEO of Halliburton, David J. Lesar, caused controversy in 2007 after announcing that he was moving to Dubai and would run operations from the Middle East. The move was believed to be in line with the company's growth in the region. Lesar said at the time: "As the CEO, I'm responsible for the global business of Halliburton in both hemispheres and I will continue to spend quite a bit of time in an airplane as I remain attentive to our customers, shareholders and employees around the world."

3. Saipem ($ 14.1 bn) Top 3 Largest oilfield services companyA subsidiary of Italian energy company ENI, Saipem is one of the largest turnkey contractors in the oil and gas industry.Founded in 1957, the Italian company has made its name handling the oilfield services for a number of challenging projects both on and offshore. With over 30,000 employees operating in all the major oil and gas producing nations, the company has earned a reputation in the industry for achieving results.

GN Decanting Centrifuge (http://www.gnsolidscontrol.com/decanting-centrifuge/)4. Transocean ($ 12.67 bn) Top 4 Largest oilfield services companyTransocean is the world's largest offshore drilling contractor. The company rents out floating, mobile drill rigs, along with the equipment and personnel needed for operations, to oil and gas companies.

6. Fluor ($ 22.326 bn) Top 6 Largest oilfield services companyIn regards to revenues Fluor finishes above both Halliburton and Baker Hughes, but due to the companies various interests in other industries only manages to finish fourth on the list. A Fortune 500 company, headquartered in the Las Colinas area of Irving Texas, Fluor employs over 41,000 people and has offices in 25 countries.

7. Weatherford International ($ 7.8 bn) Top 7 Largest oilfield services companyWeatherford is a provider of products and services that span the drilling, evaluation, completion, production and intervention cycles of oil and natural gas wells.Started in the US in 1948, Weatherford employs around 46,700 employees and operates in more than 100 countries. The company provides a whole host of services including drilling, evaluation, conveyance, completion systems, production, maximising recovery and well optimisation.GN Oilfield Sand Pump (http://www.gnsolidscontrol.com/sand-pump/The company works extensively in the Middle East with a number of high profile companies including the ubiquitous Saudi Aramco and ADNOC as well as having ongoing projects across the Gulf region.

8. BJ Services Company ($ 4.08 bn) Top 8 Largest oilfield services companyFounded way back in 1872 BJ Services Company is based in Houston, Texas. The company has over 13,000 employees and operates in over 50 countries worldwide.BJ Services provides various oilfield services including, pressure pumping, cementing and stimulation services, remedial work, completion tools, completion fluids, casing and tubular services, production chemical services, and pre-commissioning, maintenance and turnaround services in the pipeline and process business, including pipeline inspection.

9. Petrofac ($ 3.34 bn) Top 9 Largest oilfield services companyPetrofac is an oilfield services company based n London. It has over 11,000 employees and operates out of 24 offices worldwide. The company has seven business units providing a variety of services to the oil and gas industry including operations management, engineering, construction and maintenance.

10. China Oilfield Services Ltd. ($ 1.23 bn) Top 10 Largest oilfield services companyThe Beijing-based China Oilfield Services Ltd (COSL), is state-controlled, but also trades on the Chinese stock exchange.Founded in 1967, COSL has around 8,500 employees and its services cover exploration, development, and production of offshore oil and natural gas operations. Its four business segments are drilling services, well services, shipping, and geophysical services.